1997 5.4 problems
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From: Hamilton, ohio
1997 5.4 problems
i ahve a 1997 ford F150 with a 5.4 in it. when towing and i come to a stop light the engin sometiems starts chugging like it wants to stall. if you take the truck out of drive it will stop the cugging or if you rev the motor. the check engin light does not come on when this is happening. the truck has had all the o2 sensors replaced but one replaced and i ahve just recently had a new fuel filter put on and trans flush. i am starting think it might be the fuel pump going but it only does it when towing so far so that does not make anysense to me. next step is a tune up and maybe all new COP's. i have also ran some injector cleaner through it severl times in the past few months. the truck idels at about 600 RPM when it is in drive. so now i am looking to you all for any help and ideas on what to do now.
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From: Louisville,Ky.
I would suspect one of 2 things . 1) most likely you have a sticking IAC valve. This controls the idle speed and it may be time for a new one. 2) and less likely, the torque converter isn't unlocking properly. It is almost like forgeting to push in the clutch when stopping when this happens..
I would suspect #1. It is located on top of the intake behind the throttlebody. It has 2 8mm bolts and a 2 wire plug on it.
I would suspect #1. It is located on top of the intake behind the throttlebody. It has 2 8mm bolts and a 2 wire plug on it.
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From: Hamilton, ohio
cool i will have to check on a new IAC. i hope it is not the torque converter. that would really suck. the truck has 75,600 miles on it but the trans only has like 50,000 on it cause when the truck had about 20,000 on it for put a new trans in it. they even installed a navigator trans in it. the trans fluid was changed once at about 40,000 miles and it was only a partial change. but if it was the torque converter wouldnt it do it more regularly?? this pretty much only happens when i tow.
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From: Hamilton, ohio
i talked to a ford tech and he said that my 600 RPM idel is a little low. he said it should be more around 750. so he thinks that its the IAC going bad and maybe a dirty throttle body. so i might as well clean my MAF while i am at it.
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From: Hamilton, ohio
ok, i will keep you posted, i am gonna give it a whirl this weekend. i have also noticed that you can sit soemtimes and watch the idel drop to about 550. the idel seems to stay about normal when the motor is cold. also when it is ideling at the low RPM it has a miss in it. but when it is not it runs really smooth.
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From: Louisville,Ky.
You might also want to scan for codes even though the light isn't lit. It may have some stored in there.
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From: Hamilton, ohio
ok, i will also give that a try. the truck is running a little smoother since i ran a bunch of injector cleaner through the system but the weather has also been alot cooler than usual.
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You might be able to just clean the IAC with throttle body cleaner. My '97 5.4 got to where it wouldn't idle without pressing the gas pedal for about 15 seconds after a cold start. It was the IAC sticking shut. Cleaning is fixed the problem for the next 50K+ miles. It was still working fine when I traded it last month. My brother-in-law is an auto technician and he said that IAC problems are very common on the 5.4.
While your there, you might as well clean the entire throttle body. Make sure you buy the "coating safe" throttle body cleaner. There is a coating on the inside of the TB that is supposed to resist soot buildup. I also had a sticky throttle plate that was cured by cleaning.
While your there, you might as well clean the entire throttle body. Make sure you buy the "coating safe" throttle body cleaner. There is a coating on the inside of the TB that is supposed to resist soot buildup. I also had a sticky throttle plate that was cured by cleaning.
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From: Hamilton, ohio
do i clean the IAC with the same stuff i clean the therottle body with?? i am going to the auto parts stoer tomorrow to get a new set of break pads for the front of it so while i m there i might as well make a long evening of workin on it.
how do you clean the IAC?? or is it pretty much self expainatory after i get it apart??
how do you clean the IAC?? or is it pretty much self expainatory after i get it apart??
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From: Hamilton, ohio
ok, after i got the brakes done i cleaned my IAC and therottle body. i did it till the cleaner had no dirt in it. test drove the truck. the truck when it started had a little trouble then when it did it blew black smoke out of it. then it ran like a champ. on the test drive the truck ran great. no missing and the RPM when the truck was in drive were about 100 RPM more than before. the truck also felt like it had more power.
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From: Louisville,Ky.
Sounds like you got it fixed. 
If it starts acting up again, then I would replace the IAC.
Over the years, the little motors in there get weak and don't respond as fast as they should which can cause low idle, surging, etc.
If it starts acting up again, then I would replace the IAC.Over the years, the little motors in there get weak and don't respond as fast as they should which can cause low idle, surging, etc.